珂朵莉与宇宙

https://ac.nowcoder.com/acm/problem/14600

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <stack>
#include <queue>
#include <string.h>
#include <cmath>
#include <bitset>
#include <set>
#include <map>
#define ll long long
const int inf = 0x3f3f3f3f;
const int mod = 1e9+7;
const double p = 3.141592653589793238462643383;
using namespace std;

//sum[r] - sum[r-l+1] = j*j
int main()
{
    ios::sync_with_stdio(false);
    int n,sum,x,num[5000005];
    ll ans = 0;
    cin >> n;
    num[0] = 1;
    sum = 0;
    for(int i = 1; i <= n; i++){
        cin >> x;
        sum += x;
        for(int j = 0; j * j <= sum; j++){
            ans += 1ll*num[sum - j * j];
        }
        num[sum]++;
    }
    cout << ans << endl;
    return 0;
}